Actually Rich not kibitzing is not a courtesy it IS a rule tournemanet rules #2115
Subject to the following qualifications, spectators are allowed at tournament tables. Kibitzing* is strictly prohibited. Table settings should have the "Allow Kibitz" box unchecked, where applicable.
Spectators should never speak at a tournament table after the match has begun, unless specifically addressed by a competitor. Although, it is common courtesy to ask if you may watch; it is not mandatory as this might be distracting. Players shouldn't be upset if the spectator does not ask for "permission" to watch, nor boot the spectator for not asking.
The hosting TD may speak at any table, as needed.
In certain special events, such as BOS or TD vs Players tourneys, where a final match is held between winners of 2 separate tourneys, there is a “tradition” of lively banter among spectators. This is acceptable, but ONLY if the competitors themselves say it is OK with them. If any competitor asks for silence, the request MUST be honored.
If any player in the match objects to the presence of any spectator, s/he must leave the table on request; no explanation necessary. Spectators that refuse to leave upon request may be booted, but the boot must always be preceded by a polite request.
The hosting TD and the HA and AA of the hosting league are always allowed to attend at any game; they may not be booted.
If a spectator tries to kibitz, s/he should be booted immediately; no request is needed.
* Kibitz is a feature of most card games, dominoes, and such, where a spectator may view the hands of the contestants. When a player uncheck it at the table, his/her hand may not be viewed.